U.S. Pat. No. 4,706,152, assigned to Texas Instruments Incorporated, relates to an enclosed break device known as the 4TM and the 5TM. An enclosed break device, according to the International Electrotechnical Commission (IEC) Standard 60079-15 second edition 2001-02, is a “device incorporating electrical contacts that are made and broken and that will withstand an internal explosion of the flammable gas or vapor which may enter it without suffering damage and without communicating the internal explosion to the external flammable gas or vapor.” The 4TM and 5TM devices which have been made in accordance with the referenced patent comply with the first edition of the IEC standard 60079-15 which requires that enclosed break devices pass a make-and-break test 3 times without communicating an internal explosion to external flammable gas or vapor.
However, such devices may not meet the requirement of the second edition IEC Standard 60079-15, which requires that an enclosed break device pass a make-and-break test 10 times.